Fluid compressors find a wide range of applications in industrial and commercial environments, from control of manufacturing processes to inflation of bubble-type enclosures such as for tennis courts, protective housings for antennas, etc. Each such application requires a particular value or range of values of pressure (or vacuum) to fulfill its intended function. These values can be obtained by appropriate choice of the size of the compressor, control of the speed at which it is driven, use of fluid flow control arrangements, etc. By way of example, a form of the last mentioned type of control is disclosed in U.S. Pat. No. 3,395,853, granted Aug. 6, 1968 to Gunther Zoehfeld, and assigned to the present assignee.
Another way to establish a desired set of operating conditions for a fluid compressor is to provide a relief valve in the high pressure side of the compressor, which valve is designed to open at pressures above a predetermined value, thereby establishing the operating pressure of the compressor at that value. While the employment of relief valves in compressor systems is known, conventional pressure relief valves suffer from certain disadvantages which limit their effectiveness. The moving member of such a conventional valve, a ball, for example, requires a guide for confining the movement of the member, which guide may bind the member or prevent proper seating because of contamination or distortion of the material of the valve itself and thereby impair operation of the valve. Moreover, such a valve often is characterized by a moving member of relatively high mass, which results in a tendency of the member to chatter and change calibration at varying altitudes. These limitations render such valves unacceptable in many applications, particularly where the compressor is being used at an unattended location and high reliability is required.